Means for mounting machine guns in airplanes



"Nov; 30, 1948. P.' H.'KEMMER ErA|;. I 2,454,806

' MEANS FOR MOUNTING gaAcHI-NE arms INAIRPLANES I 5 Sheets-$heet 2 Filed July 9,- 194a Nov. so, 1948. v

Fired Jul 9, 194;

P. H. KEMMER ETAL MEANS FOR MOUNTING MACHINE Gums IN AIRPLANES 5 Sheets-Sheet 3 1 44/4- /7. ifs/9M5 6424 E. EE/C/IEP? CHARLES 5. 5077'; JR.

Nov. 30, 1948. p.11. E M J ETAL 2,454,806

nuns FOR MOUNTING MACHINE suns IN AIBrLANEs Filed July 9', 1943 5 hee'ts-Sht' 4 Pan 2 l JUPPLV 5 Patented Nov. 30, 1948 l MEAnsnoaii/roUN-TrNG MACHINE GUNS 'f 'INAIRPLANES resin. Kemlrner, Fairifield, and m1 E. Reichert j and (Sh ks Application July i ntt, Jr.,' Daytongohio 1943, Serial No. realist:

k arcl. 89%3151) (Granted under the act of March 3, 1883, as

factured and used by or for Government ior governmental purposes, without the payment to us of any royaltythereon. 1 A

This invention relates to means'f-or mounting machine guns or rapid firingcannon in airplanes and its principal object is'to increase thefire power and field of fire of airplanes without a proportionateincrease in the number of guns and weight, so that heavy fire may be directedtoward an enemy approaching from any angle what' ever. Another object is to provide a gun mount and arrangement'which may be readily adapted to known types of airplanes; and especially to the ends of the fuselages or the nacelliesP-Ajiurther object is to provide an airplane having turrets so located and shaped as'to permit higher airplane speeds and longer ranges "without -los sin ofiensive or defensive fire power. Af urther 01 ject is to provide a turret "whose outside contour is such that it blends intothe'fuselage without any break in the fairing lines. Other objects will appear from the following description of the preferred embodiment of the invent-ion.

As disclosed in the Funk PatentNo. $236,312,

dated March 25, 1941, it is old to provide a retatable turret at the nose of an airplane and to mount a machine gun in a ball joint carriedon a, slidable panel which may move the gun longitudinally of the rotatable turret. Such an jarrangement will permit an extreme elevation or traverse of perhaps 45 in either direction, or in other words'will provide .a fieldoffire which is approximately a cone with a vertex angle of notmore than 90. However, at and near"the--limits-oi movement of the machine gun it cannot be aimed accurately because of the position of thegunner. Furthermore, a cone of fire of 90 leaves a very large area above,'below; to either side of andto the rear of the airplane which cannot be jde fended unless the airplane changes its-course and regardless of frequent changes-fin course an "airplane armed as described insaid patent will be nearly helpless if approached fron itherear and above by a plane of equal or greater speed. more fully explained in the periodical Flight? issue of February 11, 1-943, pp. -144, 445, the Messerschmitt 210A-1 airplane-has not only two fixed machine guns and twofixed cannon inthe nose but also two 'rearwardly firing machine guns in two barbettes located onoppositesides of the fuselage about halfway between thenose and the tail, both barbette guns being sighted and remotely controlled :by an electrical system Jop erated by the rearugunnerr' These guns can be The invention described herein may be mania Lamended April 30, 1928; 87.0 O..G. 757) elevated approximately 35 above or below center and can be traversed through approximately 39. Obviously this airplane while formidably armed may be approached from many angles without encountering defensive fire. The famous B-1 'l (Flying Fortress) bombers have no blind spot; but this is accomplished at the expense of many guns located in the turrets and barbettes which project from the fuselage at difierent points and materially reduce the speed and range of these bombers.

In accordance with the invention, a bomber or other airplane is provided with nose and tail turrets preferably at opposite ends of the fuselage,

each housing one or more machine guns or rapid firing cannon, and these-turrets are rotatable substantially about the lonigtudinal axis of the fuselage, while the machine guns are swingable on axes substantially at right angles to said longitudinal axis. The preferred arrangement permits the swinging of each machine gun or cannon through an'arc of 226, the result being that a single gun at the nose and another at the tail may together defend the entire field surrounding theairplane. Our invention also contemr plates the location of guns at various other points as will be described.

In the accompanying drawings forming a part of thisspecification:

Fig. 1 is a diagram in plan showing a medium bomber in dot and dash lines equipped with nose and tail turrets embodying the invention, also indicatingin full lines the fields of fire of the severalsets of machine gu s; the extent of projection of the machine guns being exaggerated;

Fig. 2 is a similar view but side elevation;

Fig. 3 is a perspective view of one of the turrets with --iour machine guns, the view being partly diagrammatic and omitting the shield and many other details;

Fig. 4 is a view from ,the rear showing diagrammatically the arrangement of the ammunition cans, ie'ed chutes,link ejection chutes and eartridge case ejection chutes relative to the ma,- chine guns;

' Fig. 515 a perspective view of a turret showing themachine guns in an extreme postion;

Fig. 6 is a wiring diagram of one form of control' means for the turret and guns, whereby the guns ar'eaimed automatically by merely pointing an aiming device at the target;

Fig; -'l is a detail in section showing the rotary mounting oraturret on the iuselage, also motor fer rotating it; and

'Figs. -8 and -9 are each diagrams in plan like Fig.

1, but showing modified arrangements of turrets on two different types of airplanes.

Referring particularly to the drawings, and first to Figs. 3, 4 and 5, each turret of the invention has a hood or shield H of an elongated cup-like form with a smooth outer surface and preferably made of sheets of Plexiglas (a transparent thermoplastic acrylic resin) united and reinforced in a conventional manner. Instead of Plexiglas, other materials such as armor plate, aluminum, plywood or opaque plastics may be used, since it is not necessary to sight through the walls of the turret. The entire shield is removably secured at its rear end by studs Ila or the like (Fig. '7) to an annular frame l2 preferably made of some light metal such as magnesium alloy or Duralumin. Anti-friction bearings, for example, roller bearings l3a, I3b, may be carried on the outside of annular frame I2 and may roll in machined slots provided in a circular base ring M secured to the forward end of the fuselage l5 of the airplane. The general plane of base rin [4 is at right angles to the longitudinal axis of the airplane, so that the turret mustrotate about said axis or about an axis parallel thereto. One or more machine guns 16, preferably four caliber .50, M2 Browning aircraft basic machine guns, preferably arranged in two pairs on either side of the medial plane of the turret, are enclosed by turret body l! except for their muzzles which protrude through slots ll, 18 in the Plexiglas. Slots I1, is are shown as extending parallel to each other from points near the secured end of the Plexiglas shield around the nose and back on the opposite side to points equally near said secured end. The length of the slots should be such as to permit traverse or elevation of the pairs of machine guns through a total angle of more than 180 and preferably of 226 as will be described. However, the slots need not be on diametrically opposite sides of the turret since the turret can be rotated in either direction through 360 to bring the slots (if confined to one side) to any desired angular position. If preferred, movable panels (not shown) may close the slots except where the machine guns project, thereby to reduce drag.

To make possible a traverse of 226 of each cannon or machine gun carried in the nose and tail turrets, a support l9 in the form of a hollow box or casing is rigidly secured at one end to the annular frame l2 to extend at right angles to the general plane of the annularframe. The hollow casing l9 provides a central longitudinal partition within the shield ii dividing the turret into two compartments each containing a pair of machine guns l6. Supported centrally of the hollow casing I9 is a circular, hollow gun mount 20 to which the guns are rigidly secured by means not shown. Gun mount 20 may be rotatable but preferably is oscillatable through a total angle of 226 about an axis at right angles to the axis of rotation of the turret. A U-shaped frame having two parallel arms 2| joined by a straight shank 22 is pivoted as at 23 upon tie plates 24 each riveted or otherwise secured to the outer ends of three converging arms 25, 26, 27. These arms are secured at their other ends to frame I2 at widely spaced points for maximum rigidity. Thus the tie plates are rigidly supported parallel to each other and in turn may assist in supporting shield II, which may be fastened by studs 28 and washers 29 (Fig. 5) outside of the tie plates. The U-shaped frame provides additional support or tying means, transmitting the load of the guns and ammunition to annular frame l2, and has its shank 22 passing through the circular gun mount 20 to extend on opposite sides thereof. The ammunition cans 30, of which there is one for each machine gun, each containing several hundred rounds of ammunition on the usual disintegrating belts (not illustrated), are secured preferably to the U-shaped frame by means not shown. The ammunition cans 30 are arranged side by side, to conserve space, which causes the lower machine gun of each pair to project about 6" beyond the muzzle of the other gun of the same pair.

vEach machine gun has a link chute 3| for dis charge of the links of the disintegrating ammunition belt, and a shell case chute 33 for discharge of the empty shells, both the links andshell cases moving first into the hollow gun mount 20 and then through the preferably open periphery of the gun mount to the interior of the hollow box or casing 19. Thus the links and shell cases do not collect in the turret to interfere with rotation and traverse of the guns, or replacement of the ammunition cans. Ammunition boosts 34 and ammunition belts 35a, 3512 are also indicated diagrammatically.

The axis of traverse or elevation of the machine guns l6 is obviously the axis of rotation of the gun mount 20 (which is also the axis of ivots 23); and this axis is far enough forward of the plane of annular ring I2 to permit the guns to fire rearwardly to a certain extent, as well as forwardly, in all angular positions of the turret. The arrangement is preferably such that each pair of machine guns in each turret may oscillate about the axis of pivots 23 through an angle of 226. 8% Figs. 1 and 2. In other words, each of the four machine guns in the preferred arrangement has a field of fire that is a spherical segment of one base, out of whch a cone of revolution having a vertex angle of 134 has been carved. Expressing the matter otherwise, the machine guns each have a field of fire substantially equal to that portion of a sphere which is generated by the complete revolution of a circular sector (having a vertex angle of 113) about the diameter of the circle of which the sector is a part.

As indicated ln'the diagrams, Figs. 1 and 2, the fuselage [5 of the two engine bombardment plane extends well forward of the wings 36 and engine nacelles 31 and with thepivot axis 23 of the guns located as described, the 226 are through which the guns of the nose turret may fire will clear the tips of wings 36 while the field of fire of the guns in the tail turret will clear the tail structure 38. As a projection of the lines indicating the arcs of fire will show, the two fields of fire of the nose and tail turrets intersect at points closer to the fuselage longitudinal axis than the total span of the wings and at a distance but slightly exceeding the extreme overall length of the bomber fuselage including the turrets. For example, if the total spanv of the wings is 114 ft. and the overall len th of the fuselage including turrets is 79 ft. 3 in., the fields of fire of the nose and tail turrets will intersect at approximately ft. 9 in. from the longitudinal axis of the fuselage. Hence the described bomber has eight machine guns which may hit an enemy when very close and at any angle whatever, yet has no turrets or barbettes which will increase the drag.

To rotate each turret, an internal ring gear 39 (Figs. 3 and 7) is secured to the annular frame I 2 and a reversible electric motor 40, controlled by means to be described, "drives a reduction gear train (not shown) in a casing 4 I, said gear train having a pinion Ma meshing with the ring gear 39 to drive it at the desired speed. To bring the ring gear, hence the turret, to a quick stop when power to motorllfl is shut oif, a solenoid brake 42 (Fig. 6) of conventional construction may be employed. To point the guns 16 toward the target, a controller 01' aiming device 50 which may have the form of a pistol, is connected electrically with motor 40. The arrangement is such that any movement of the aiming device 50 (which may be located in the pilots cabin or anywhere on the airplane) isfaithfully reflected in corresponding movementiof the guns !6. 'Ihe control to be described is adapted from the Mittag expired Patent No. 1,547,435, .dated July 28, 19.25. While only the control for turret rotation is described in detail, the samercontrol is used to .efiect elevation .or traverse of the guns, orin other words, two .duplicate electrical control systems are used, one acting responsive to movements of the aiming device about .one axis, the other responding in the same manner to movements of the aiming de vice about an axis at right angles to the first axis. Thus the aiming device 50 causes suflicient rotation of the turret and traverse of the guns to make the guns aim in the direction in which the aiming device points. Firing is controlled b conventional means not shown.

A field winding 53 is rotatably mounted and driven by movement ofthe controller 59 about an axis parallelto the longitudinal axis of the plane, and is energized from the source of power S. Co-operatively associated with field winding 53 is a stationary polycircuit armature winding 54. Field winding 53 and armature winding '54 together constitute an inductive device which is sensitive to the position .of the controller and which sends out electrical impulses to a second inductive device including a winding55 which is rotatably mounted, and a three phase armature winding 56. The described inductive devices produce an alternating E. M. F. which has a value substantially proportional to the angular disagreement .or variance between the controller or pointer and .the guns and which has a direction relative to the alternating currentsupply source that is determined by the direction of thisdisagreement. The guns are movedabout the axis .of frame 12 by motorcll which is an A. (3. motor controlled in responsekto the voltage induced in winding 55. Motor .40 is shownas athree phase induction motor having a Y connected three phase winding .51 and squirrel cage rotor winding (not indicated) whichhas sufiicient resistance so that the motor willnot run as a single phase induction motor.

For the control of motor 40 the E. M. F. induced in winding (when there is angular variance between the controller and the guns) is impressed upon the input or grid circuits of two electron discharge amplifying tubes and Bi shown as ofthe three electrode type. This connection is preferably effected through a transformer 62 the secondary 63 of which is provided with a central tap 64 so that one-half of the secondary 63 is connected in the input or. grid circuit of tube so while the other half is.connected in the input or grid circuit of tube .Bl. To improve the operation, condensers 65, .66 are connectedacross sections of the secondary. The output or plate circuits of the tubes are connected to the two halves .of the primary 69 of transformer ill.

Tubes .50, '5] are thus connected to a push-pull or two wave circuit so as to reproduce both halves of the E. M. F. wave induced in winding 55 and thus impress an A. C. on transformer 10. Tubes 6!], 6l amplify the power output of winding 55.

Forfur-ther amplification the secondary H .of transformer 1-0 is provided with a central tap 13 and its two halves are connected in the input or grid circuits of two electron tubes 14, -15, the output or plate circuits of which are-connected to the two halves of the primary H3 of a transformer 19. Tubes 14, *l5'are connected in pushpull or two wave circuits in the same manner as tubes 50, BI, their function being to amplify the output of the two latter tubes. As thus arranged, the winding 55 supplies only the very slight amount of power required .to energizethe input circuits of tubes 60, iii.

The secondary oftransformer 18 is provided with a central tap'BI which is connected through a conductor '82 to one side of the A. C. supply S, the opposite side of the supply source being connected to one terminal 83 of motor winding 5]. The other terminals 84, 85, of said motor winding are connected to the terminals of secondary 80. This connection of transformer 19 is similar to the well known Scott transformer connection for converting two phase to three phase power. It has been found {that the power output from the electron tube'amplifying devices has quite a large phase displacement with respect to the A. G. supply '8. This power output having one direction is impressed on the secondary 80, the terminals of which are connected to two of the motor winding terminals while the source of supply S corresponds to the teaser coil of the "Scott connection and is connected in central tap ill to the remaining motor winding terminal. system of connections gives an approximately three phase source of supply for motor 4-0.

In the operation of the system, when the winding 55 is at right angles to winding 53 as illustrated in the drawing, corresponding to a conditionof angular agreement between the controller and the guns, no voltage is induced in winding 55 and consequently no power is supplied to motor 40. The single phase current from source S will have-no eifect in causing rotation of the motor. Now assuming that the controller is moved in one direction, a voltage will be induced in winding 55 which will result in power being supplied from the amplifying devices to motor 40 causing rotation of the motor to move the turret until the guns are moved into angular agreement or parallelism with the controller.

Since the voltage induced in winding 55 depends on the amount of the angular variance or disagreement, the power supplied to the motor will likewise depend upon the amount of the angular disagreement. Whenthe guns point exactly in the same direction as the controller the three phase power is cut off from the motor and it immediately stops. In case the controller is moved inthe opposite direction, it will be observed that since the voltage induced in winding 55 is in the opposite direction, that is, displaced 180 in phase,-the power supplied to terminals 84, 85 will be reversed in polarity, so that rotation of the motor will be reversed and the guns will therefore be moved in the proper direction to follow the controller.

To elevate'and lower or traverse the guns, a motor 86 (like motor 40, see Fig. 3) drives a pinion 81 through a reduction gear in box 8,8, said Pinipn me n 'w a me a nswer ear t9 secured to oneside of the casing l9 and surrounding the gun mount 20. Annular gear 89 may subtend an angle of slightly more than'226, since its function is to efiect oscillation of the gun mount through said angle (or any smaller angle desired) when the motor 86 is energized. Motor 85 is conveniently mounted on the shank 22 and is controlled through a circuit exactly like the one illustrated in Fig. 6, hence not shown. The controller or aiming device is elevated and lowered at the will of the, gunner, and the gun mount 20 will swing the machine guns through exactly the same angle.

In Figs. 1 and 2 an additional pair of machine guns 90 are shown as carried within the fuselage on each side thereof to increase the fire power of the bomber especially if attack comes simultaneously from several different hostile aircraft. The preferred arrangement is to mount each pair of guns on a cylindrical carrier member SI supported on bearings (not shown) carried inside the fuselage so as to rotate about a transverse axis at right angles to the longitudinal axis of the airplane. Preferably each pair of guns 90 is directly opposite the other pair and besides the described angular movement each pair of guns may swing through a total angle of about 130 about an axis at right angles to the axis of revolution of the carrier 9|. However, a minimum total traverse of 90 is considered to be within the scope of the invention. By known mechanisms, either the fire may be discontinued automatically when the angles of these guns are such as to point at some part of the plane they are carriedon, or else the guns are automatically forced to travel in a path which prevents shooting at said plane. The cylindrical carrier members iii are wholly inside the bomber fuselage so that there are no projecting parts except portions of the gun barrels. The gun swinging and rotating mechanisms may be similar to those described. Members of the bombers crew may crawl beneath or over the carriers 9!, which are end to end, in the event it is necessary to pass from the tail to the nose of the plane, or vice versa. Window panels 92 are on opposite sides of the carrier mounts so as to give a good field of vision for aiming these side guns. The described arrangement will permit the gunners to bring the fire of ten machine guns, or severalcannon plus machine guns, on either side of and at many angles above and below the bomber;

In Fig. 8 we show an arrangement wherein the airplane 85 has our turrets on each nacelle after body 96, and also on the forward, portion of a pusher type nacelle 91. Fig, 9 shows the turrets on the forward and after portions of the central body 98 of a twin boom type of airplane 99. A single turret at either end may be used. These two views also exaggerate the extent of projection of the machine guns.

While the described turrets enclose the ammunition cans, it is within the scope of the present invention to locate them to the rear of the main supporting ring is, i. e., within the fuselage, the cans then rotating with the annular-frame I 2. Belt feeds of known construction would carry the ammunition belts from the several cans to the machine guns. This modification would be advantageous in that the turrets could be smaller, the ammunition capacity would be materially increased, and the removal of empty cans and replacement with full ones would be facilitated. However, no claim is made to this specifically.

While we have described our invention as embodied in a concrete form and as operating in a specific manner, it should be understood that We do not limit the invention to the described matter since various modifications will suggest themselves to those skilled in the art without departing from the spirit of the invention.

Having described an embodiment of our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

l. A gun turret structure having a field of fire covering a spherical sector with a vertex angle greater than 180 for use on opposite outboard positions of an aircraft to provide a complete sphere of fire about the aircraft comprising; an annular base member adapted to be secured to an aircraft structure; a cup-shaped turret member having an axis of revolution passing concentrically through an open end thereof, said turret member adjacent its open end and said annular base member being juxtaposed in relatively movable concentric relation wherein said turret member may rotate about said axis of revolution throughout 360; operator-controlled power actuated means operatively associated with said cupshaped turret and annular base members to power rotate said cup-shaped turret member; a U- shaped gun mount journaled at the ends thereof within said cup-shaped turret member rotatable about an axis perpendicular to said cup-shaped turret member axis of revolution through an angle greater than a turret support having a circular opening therein concentric to said gun mount axis in which the closed portion of said U-shaped gun mount is operable in an arc in close relation to the periphery of said circular opening; gun means mounted on said gun mount to point substantially radially outward from said gun mount axis of rotation, said cup-shaped turret member having slots therein through which said gun means are operative; and operator-controlled power actuated means operatively associated with said turret support and said U-shaped gun mount to power rotate said gun mount about its axis whereby said gun means are actuatable to be directed throughout a sperical field of fire greater than a hemisphere.

2. A gun turret structure having a field of fire covering a spherical sector with a vertex angle greater than for use at opposite stations of an aircraft to provide a complete sphere of fire about the aircraft comprising; an annular base member adapted to be secured to an aircraft structure; an annular turret member having journal means extending from one plane thereof to provide a journal axis parallel to a diameter of said annular turret member, said annular turret member being journaled to said annular base member along the annular portion thereof to rotate 360 about an axis of revolution common to both said annular members; a gun mount having trunnions journaled in said journal means; a turret support fixed to said annular turret member and extending laterally therefrom on the same side as said journal means having a circular opening therein with the center thereof lying on said journal axis; operator-controlled power means operatively associated with said gun mount and said turret support for rotating said gun mount in excess of 180 about said journal axis and operator-controlled power means operatively associated with said annular base and annular turret members for rotating said annular turret member throughout 360 with respect to said annular base member; guns mounted in said gun mount pointing substantially radially outward from said joiunal means axis; and a gun turret cover enclosing said gun turret structure 9 having slots therein through which said guns fire and being supported on said annular turret and turret support members whereby said guns can be pointed in any direction in a spherical field of fire greater than a, hemisphere.

3. A gun turret structure for aircraft comprising; an annular base ring adapted to be secured to an aircraft structure; and elongated cup-like turret member having an axis of revolution passing concentrically through an open end thereof, said turret member adjacent its open end and said annular base ring juxtaposed in relatively movable concentric relation wherein said turret member may rotate about said axis of revolution through an angle of 360; an internal ring gear attached to said turret member adjacent to and in the plane of the open end thereof; operatorcontrolled power-actuated means in fixed relation to said annular base ring operative to rotate a pinion gear operatively associated with said internal ring gear; a gun mount journaled Within said cup-like turret member rotatable about an axis perpendicular to said cup-like turret member axis of revolution; an internal segmental ring gear subtending an angle of at least 226 connected to said cup-like turret member in operative association with an operator-controlled power-actuated pinion gear fixed for operation relative to said gun mount for rotating said gun mount substantially in excess of 180 about its axis; and at least one gun fixed to said gun mount to point radially outward from said gun mount axis of rotation for firing through a slot in said turret member whereby said gun is adapted to havea field of fire substantially equal to a i which the sector is a part.

PAUL KEMMER. CARL E. REICHERT. CHARLES S. BUTT, JR.

REFERENCES orrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,182,317 Rogala May 9, 1916 1,547,435 Mittag July 28, 1925 2,034,223 Brady Mar. 17, 1936 2,182,722 Gavardie Dec. 5, 1939 2,199,971 Sanders May 7, 1940 2,233,918 Fey Mar. 4, 1941 2,242,198 Woods May 13, 1941 D. 134,426 McDonnell Nov. 24, 1942 2,307,582 Haberlin Jan. 5, 1943 FOREIGN PATENTS Number Country Date 77,718 Switzerland May 16, 1918 310,670 Germany Dec. 20, 1919 764,841 France Mar. 12, 1934 791,106 France Sept. 23, 1935 800,959 France May 11, 1936 447,931 Great Britain May 28, 1936 803,012 France June 22, 1936 341,938 Italy July 16, 1936 344,261 Italy Nov. 2, 1936 515,993 Great Britain June 29, 1937 475,377 Great Britain Nov. 18, 1937 482,325 Great Britain Mar. 28, 1938 513,338 Great Britain Oct. 10, 1939 857,251 France Apr. 15, 1940 OTHER REFERENCES Heavier Guns, etc., Popular Mechanics, page 535, April 1937.

Aircraft Armament, Aviation, pages 34, 35, September 1938. 

